Move widow-avoiding code from RenderBlock down to RenderBlockFlow.

Source/core/rendering/RenderBlockFlow.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003-2013 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ skipping 296 matching lines @@
     FlowThreadType flowThreadType(const RenderStyle*);
 
     RenderMultiColumnFlowThread* createMultiColumnFlowThread(FlowThreadType);
     void createOrDestroyMultiColumnFlowThreadIfNeeded(const RenderStyle* oldStyle);
 
     void updateLogicalWidthForAlignment(const ETextAlign&, const RootInlineBox*, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float& availableLogicalWidth, unsigned expansionOpportunityCount);
     void checkForPaginationLogicalHeightChange(LayoutUnit& pageLogicalHeight, bool& pageLogicalHeightChanged, bool& hasSpecifiedPageLogicalHeight);
     bool shouldRelayoutForPagination(LayoutUnit& pageLogicalHeight, LayoutUnit layoutOverflowLogicalBottom) const;
     void setColumnCountAndHeight(unsigned count, LayoutUnit pageLogicalHeight);
 
+    bool shouldBreakAtLineToAvoidWidow() const { return m_rareData && m_rareData->m_lineBreakToAvoidWidow >= 0; }
+    void clearShouldBreakAtLineToAvoidWidow() const;
+    int lineBreakToAvoidWidow() const { return m_rareData ? m_rareData->m_lineBreakToAvoidWidow : -1; }
+    void setBreakAtLineToAvoidWidow(int);
+    void clearDidBreakAtLineToAvoidWidow();
+    void setDidBreakAtLineToAvoidWidow();
+    bool didBreakAtLineToAvoidWidow() const { return m_rareData && m_rareData->m_didBreakAtLineToAvoidWidow; }
+
 public:
     struct FloatWithRect {
         FloatWithRect(RenderBox* f)
             : object(f)
             , rect(LayoutRect(f->x() - f->marginLeft(), f->y() - f->marginTop(), f->width() + f->marginWidth(), f->height() + f->marginHeight()))
             , everHadLayout(f->everHadLayout())
         {
         }
 
         RenderBox* object;
@@ skipping 29 matching lines @@
     MarginValues marginValuesForChild(RenderBox* child) const;
 
     // Allocated only when some of these fields have non-default values
     struct RenderBlockFlowRareData {
         WTF_MAKE_NONCOPYABLE(RenderBlockFlowRareData); WTF_MAKE_FAST_ALLOCATED;
     public:
         RenderBlockFlowRareData(const RenderBlockFlow* block)
             : m_margins(positiveMarginBeforeDefault(block), negativeMarginBeforeDefault(block), positiveMarginAfterDefault(block), negativeMarginAfterDefault(block))
             , m_paginationStrut(0)
             , m_multiColumnFlowThread(0)
+            , m_lineBreakToAvoidWidow(-1)
+            , m_didBreakAtLineToAvoidWidow(false)
             , m_discardMarginBefore(false)
             , m_discardMarginAfter(false)
         {
         }
 
         static LayoutUnit positiveMarginBeforeDefault(const RenderBlockFlow* block)
         {
             return std::max<LayoutUnit>(block->marginBefore(), 0);
         }
         static LayoutUnit negativeMarginBeforeDefault(const RenderBlockFlow* block)
         {
             return std::max<LayoutUnit>(-block->marginBefore(), 0);
         }
         static LayoutUnit positiveMarginAfterDefault(const RenderBlockFlow* block)
         {
             return std::max<LayoutUnit>(block->marginAfter(), 0);
         }
         static LayoutUnit negativeMarginAfterDefault(const RenderBlockFlow* block)
         {
             return std::max<LayoutUnit>(-block->marginAfter(), 0);
         }
 
         MarginValues m_margins;
         LayoutUnit m_paginationStrut;
 
         RenderMultiColumnFlowThread* m_multiColumnFlowThread;
 
+        int m_lineBreakToAvoidWidow;
+        bool m_didBreakAtLineToAvoidWidow : 1;
         bool m_discardMarginBefore : 1;
         bool m_discardMarginAfter : 1;
     };
     LayoutUnit marginOffsetForSelfCollapsingBlock();
 
 protected:
     LayoutUnit maxPositiveMarginBefore() const { return m_rareData ? m_rareData->m_margins.positiveMarginBefore() : RenderBlockFlowRareData::positiveMarginBeforeDefault(this); }
     LayoutUnit maxNegativeMarginBefore() const { return m_rareData ? m_rareData->m_margins.negativeMarginBefore() : RenderBlockFlowRareData::negativeMarginBeforeDefault(this); }
     LayoutUnit maxPositiveMarginAfter() const { return m_rareData ? m_rareData->m_margins.positiveMarginAfter() : RenderBlockFlowRareData::positiveMarginAfterDefault(this); }
     LayoutUnit maxNegativeMarginAfter() const { return m_rareData ? m_rareData->m_margins.negativeMarginAfter() : RenderBlockFlowRareData::negativeMarginAfterDefault(this); }
@@ skipping 95 matching lines @@
 
 // END METHODS DEFINED IN RenderBlockLineLayout
 
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderBlockFlow, isRenderBlockFlow());
 
 } // namespace WebCore
 
 #endif // RenderBlockFlow_h